Yeah... glomerulus is the answer... the mini-filtration system
of the kidneys that differentiate molecular size and allows it to
pass through into the renal tubules (proximal convoluted tubules,
loop of henle, distal convoluted tubules, collecting ducts --- most
of the vital ions get absorbed back into the circulation, that's
why you have arteries and veins surrounding the tubules)...
Glomerulus if seen in the cut section view, you will appreciate
it's curly appearance. Well done!
